Frequencies of Borrelia burgdorferi-reactive T lymphocytes in Lyme arthritis.

Using a limiting dilution system, frequencies of Borrelia burgdorferi-reactive T cells were determined in the blood and synovial fluid of four patients with chronic Lyme arthritis (LA), one patient with acrodermatitis chronica atrophicans (ACA), two patients with other inflammatory joint diseases, and two healthy individuals. B. burgdorferi-reactive precursor T cells ranged from 1/750 to 1/8220 in case of LA and ACA patients and from 1/820 to 1/31 400 in case of controls. In vivo activated B. burgdorferi-reactive T cells were almost absent in control subjects. With one exception, they were detected in LA patients at frequencies ranging from 1/1 300 to 1/15 400. Interestingly, even after successful antibiotic therapy of LA patients, similar frequencies of in vivo activated B. burgdorferi-reactive T cells were observed in the peripheral blood, provided that low cell concentrations were used for culture. At higher cell numbers, the fraction of B. burgdorferi-reactive T cells apparently dropped, suggesting regulatory phenomena.